Improvement in artificial legs



UNTTEDu STATES PATENT OEEICE.

ANTON MENNEL, OF NEYY YORK, N. Y.

IMPROVEMENT IN ARTIFICIAL LEGS.

Specification foriming part of Letters Patent N0. 49,645, dated August 29, 1865.

To all whom it may concern.'

Be it known that I, ANTON MENNEL, of the city, county, and State of New York, have invented a new and useful Improvement in Artiticial Legs; and I do hereby declare that the following is a full, clear, and exact description of the saine, which will enable those skilled in the art to make and use it, reference being had to the accompanying drawings, forming part of this description, in which-m Figure l represents a longitudinal vertical section of this invention when the leg is stretched. Fig. 2 is a similar section of the same when the leg is bent and in the position to take a step.

Similar letters of reference in both views indicate corresponding parts.

This invention consistsin extending thelower end of the artificial tibia below the edge of the artificial foot to such a distance that by the same a positive stop is formed, whereby the ankle-joint is rendered rigid as soon as the. leg reaches an upright position, and the wearer of the leg is enabled to take a step with perfect safety, and without danger ot' losing his balance when his entire weight is thrown on one leg while the other leg is lifted for the next step. This stop strikes against the inner surface of' the artificial heel, which is made particularly strong to prevent its' being forced out, and the force ofthe blow ofthe stop against the inner surface of the heel is softened down by interposing an elastic pad of india-rubber or other suitable material. The knee-joint ofthis artificial leg also presents some novel features, as far as the position ofthe spring is concerned. This spring extends from the back part of the shell of the artificial thigh, over the fulcrumpin of the knee-joint, to a pin or rod which is situated below the fulcrum-pin, parallel with the same and slightly in front of it, in such a manner that the power of the spring nearly ceases to act when the .knee-joint is straightened out, and all blows are avoided, which, with ordinary knee -joints, result from the spring bringing the thigh part up with considerable force against the upper end of the leg or the inner part of the joint.

A represents the shell of my artificial leg, which is made of thin strips of wood glued together, so as to cause the fibers of the wood to cross each other, whereby great strength is obtained with theleast possible weight, though it must be remarked that the mechanism which forms the subject-matter of this present invention is applicable to shells of any desirable construction.

The artificial thigh B is connected with the leg O by the knee-joint D, and the leg connects with the foot E by the ankle-joint F. This joint is formed by a pin, c, which passes through the sides of the leg and those of the foot, and these sides are strengthened by metal plates secured to them in any suitable manner. The leg, or, more properly speaking, the artifjcial tibia, extends down below the edge of the foot and nearly to the sole to form a positive stop, b, and when the leg takes a step and is brought up from the position shown in Fig. 2 to that shown in Fig. l, said stop strikes the inner surface of the artificial heel c, and thereby the position of the legis rendered safe, and the wearer ot' the leg runs no risk of losing his or her balance while taking a step with the other leg. The great importance of this stop is apparent from the fact that my first experiments made therewith have been unsuccessful because the heel was forced out, and not until I had made the same with peculiar strength and care did it resist the action of the stop. Said stop comes up against the heel with great force at every step, and in order to soften the blows I have applied an elastic pad, d, to the stop, as clearly shown in the drawings. This pad is made ot' india-rubber or other suitable material, and it may be fastened to the stop, as shown, or to the inner surface of the heel, if desired. i

A spring, c, serves to raise the toes from the ground whenever the foot is raised for a new step. This spring is secured by means of a pin,f, in the lower end of the leg C, and it is adjustable from below by a strap, g, which extends round a pin,'h, placed in a recess in the sole, the length ot' said strap being adjustable by a buckle or any other suitable means. This spring is short, cheap, and light, and it fulfills its function with the best possible effect.

The knee-joint D is produced by a pivot, t', which passes through the sides of the thigh B and ofthe leg U, and these sides are strengthened by metal plates or brackets secured there to by screws, or in any other suitable manner.

The spring j, which serves to straighten out the knee-joint, whenever the leg is brought in the proper position to allow this, is secured at its upper end to astrap, K, provided with several holes which can be made to hook over a stud, l, projecting from the inner rear surface ofthe thigh B. The lower end of said spring is fastened to a rod or pin,m,which is situated slightly in front and somewhat below the fulcrum-pin i of the knee joint, and extends through the sides ofthe leg C, parallel to said pin i'. When the leg is straightened out this spring presses very light against the fulcrumpin, and its power is nearly spent, so that the outer part ot' the knee-pau comes up with a Very light blow against the upper portion of the leg, and every disagreeable effect resulting from such blows is avoided. As soon as the Aknee-joint is bent the spring bears hard against the fulcrum-pn z', it is strained, and it exerts the necessary power to straighten theleg whenever it is permitted to do so. By changing the strap k from one hole to the other, or the stud l, the power of the spring' can be regulated. By this arrangement of the pin m parallel to fulcrum-pin i the power of the spring is properly regulated, and, furthermore, the

shell of the leg is braced without causing any perceptible increase in its weight.

By the great simplicity of my mechanism, and by the peculiar construction of the shell of my leg, I am enabled to construct legs cheap, strong, durable, and light, which is the great desideratum ot' persons compelled to wear the same.

Having thus fully described my invention,

what l claim as new, and desire to secure by ANTON MENNEL.

Witnesses W. HAUFF, E. HAUFF. 

